I continue to be impressed with the built in HDR mode on the Canon 6D
. Keep in mind that this is standing, hand held. Not bad!
Canon 16-35mm 2.8 L II
, 1/200, f8, ISO 400 - Very Light Editing with Camera RAW.
I find myself using it more and more. Its just quicker, both to shoot and process. I think with a grad filter (which I usually do use) for the horizon and HDR mode on the camera, and it should be very, very easy to even better results.